Insulin therapy can control glucose levels in patients with type II diabetes. Because of insulin resistance, high doses may be required initially to attain satisfactory control; however, also because of insulin resistance, hypoglycemia with insulin therapy is much less common among patients with type II diabetes than among those with type I diabetes. Insulin therapy need not be permanent. In some cases, temporary worsening of disease is the result of glucose toxicity and insulin can be discontinued or doses reduced when disease severity subsides. On the other hand, beta-cell failure is progressive, and with long duration of diabetes, permanent insulin therapy may be necessary to achieve satisfactory glucose control.